This invention relates to a product for breaking rock using a propellant.
During mining and other excavation processes use is typically made of an explosive to break rock. Rocks which are released during blasting are of different sizes and shapes. Some rocks are too large to be handled by available equipment. In other instances rocks which are channelled through an ore pass or box hole can become interlocked in such a way that passage through the ore pass is blocked.
Different techniques exist for breaking rocks which are in different positions, for example on the ground, or in or above an ore pass or a box hole. Reference is made in this respect to the specifications of U.S. Pat. Nos. 5,233,926 and 2,247,169 which categorize certain situations and which propose techniques for addressing attendant problems.
When an explosive material is used to fracture a problematic rock the energy which is released, during the resulting blast, can be at such a high level that surrounding supporting structure is damaged. This is unacceptable. On the other hand it can be dangerous to place a charge, whether explosive- or propellant-based, in a rock which is at an overhead position.
In some situations a plurality of holes must be drilled into one or more rocks which must be fragmented or displaced. For safety reasons it is generally not advisable to drill a hole, charge the hole and then drill a successive hole. It is quite possible under these conditions that the drill can penetrate an explosive which has previously been positioned. The drill might cause the explosive to be ignited. The consequences of unwanted ignition can be severe.
An object of the invention is to provide a rock breaking product which facilitates a secondary rock breaking process and which offers a high degree of safety.